Old-Growth Forests Under the Sea
UMaine marine research part of global effort to save ancient
deepwater corals
Dropping from the sun-drenched ocean
surface to the deepest reaches of the sea floor isn't for everyone. The
cold, bone-crushing depths are as friendly to human life as the surface
of Mars. To make the journey, researchers Les Watling and Anne Simpson
crawl into a small submarine named Alvin, the U.S. Navy's deepest diving
submersible, that has all the roominess of the first space capsule. They
prepare to dive knowing their survival depends on protection from the
very environment they want to study.
The two scientists and the pilot of the research sub are surrounded by
brightly lit control panels. On video monitors, they watch day turn to
inky darkness as the sub descends. Alvin's strobe lights and constantly
pinging sonar guide the way down.
More than a mile under the sea, the show really begins. Peering through
a 3-inch-thick window about the size of a salad plate, the researchers
see the opening act — zooplankton glowing luminescent in response to the
sub's lights.
"It looks like you're surrounded by stars," says Simpson, describing the
scene. "It's like going to the moon."
Beautiful as they are, it isn't flashy zooplankton that Simpson and
Watling are after. The University of Maine researchers are in search of
ancient deepwater corals, subjects that have captured the attention of
ocean scientists and fishery managers around the world in recent years.
The reason is simple: Researchers have found that corals are far more
abundant in deep northern seas than anyone had expected as little as
five years ago.
Coral reefs have been discovered in deep water from Florida to
Newfoundland and Portugal to Norway, and as far north as the Arctic
Circle. Fishing records suggest that these diverse marine communities
support commercially important species, including groundfish like cod
and haddock. In Nova Scotia, fishermen, using long lines and hooks
rather than nets that essentially clear-cut the ocean floor, have led
deepwater coral preservation efforts.
Watling and Simpson are studying the marine animals' basic biology — how
these corals grow and reproduce. They and other scientists also are
driven by a sense that time may be running out. Not long ago, corals
were well beyond the reach of fishing technology. Today, as trawlers
reach deeper, they are damaging coral beds that have been virtually
unchanged for millennia.
"Most of these deepwater corals are pretty old," says Watling, a UMaine
marine biologist and member of the National Research Council Panel on
Marine Biodiversity. "They're the marine equivalent of old growth
forests. There's a lot of concern that fishing gear can wipe out things
that have managed to survive for a very long time.
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Anne Simpson examines the coral species Paragorgia.
Photo by Linda Healy
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Other species of deepwater
corals studied by UMaine researchers include Metallogorgia,
Corallium and Iridogorgia.
Coral photos courtesy of
Les Watling
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"The real issue right now is that
people are starting to fish into 1,000 meters of water. Off Canada and
Norway, where large concentrations of these corals have been found, they
are starting to get hit by fishing gear. The same is true in other parts
of the world. Fishing gear is causing real problems for deepwater
corals. So there's a concentrated effort to find out as much as we can
about them."
During their dives on the Alvin last year, Watling and Simpson, a Ph.D.
student, didn't see large coral reefs. They were exploring undersea
mountainous regions known as seamounts — volcanic remnants of the
Atlantic's violent birth — that extend off the New England coast north
of Bermuda toward the mid-Atlantic ridge. There in Alvin's lights they
saw coral trees and fans hanging from steep, 800-foot-high cliffs and
spread in patches across the seamount tops.
"They were the only things sticking up off the seafloor. They're what
you notice, like cactus in the desert," says Simpson.
These denizens of the dark, some as tall as sunflowers, include many
cousins of the colorful coral found in tropical reefs in shallow waters.
Living coral animals, also known as polyps, are related to sea anemones
and jellyfish. Not much more than a mouth with a gut and smaller than a
thimble, they attach themselves to rocks and other hard surfaces. As
they multiply, the well-known skeletal formations slowly build below
them.
Watling says you can think of them as "giant condominiums, housing
projects for small animals." Coral polyps are classic opportunists,
depending on plankton and other drifting particles for food.
While the abundance of corals in northern waters was a surprise, their
existence has been documented throughout history. Reports from the
mid-18th century indicate that North Atlantic fishermen occasionally
brought up pieces of coral in their nets. At that time in Europe, corals
were sought for their medicinal powers and traded as necklaces and
bracelets. (Biomedical researchers have since confirmed the some corals
contain compounds with health benefits.)
Destruction of deep corals means more than the loss of a biological
treasure, says Watling. He is one of the more than 1,100 scientists
worldwide who signed a petition in February calling on the United
Nations and world governments to protect deep corals by restricting
deep-sea trawling. At stake are rich marine habitats, a potential source
of new medicines, and a scientific record of climate and ocean
conditions stretching back, in some cases, thousands of years.
One of the questions he and Simpson hope to answer relates to coral
remediation. How long would it take a damaged reef to rebuild?
Scientists already know that deep-sea corals grow slowly; chances are
rebuilding takes longer than the average human lifetime.
Against this background of concern, Watling and Simpson are working to
understand how deep-sea corals eat, grow, reproduce and interact with
other animals. Simpson is focusing on reproduction.
With the help of Kevin Eckelbarger, director of UMaine's Darling Marine
Center, she is using a powerful transmission electron microscope to look
at the detailed structures of egg- and sperm-producing tissues. Since
understanding the evolution of deep-sea corals can be difficult, Simpson
hopes that reproductive tissues may provide new information that will
help to resolve some of these questions.
by Nick Houtman
May-June, 2004
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